“It’s slightly longer on top and swept to one side like all the lads have. There’s no colours, it’s not like he’s been running around with a Mohawk. He’s absolutely devastated. He’s always been good at school.

“He’s always worked hard and tried his best.

“I think he’s getting to the point where he feels slightly victimised. I said ‘you’re pushing him to a point he’s going to turn around and rebel’. I can see his point of view to a certain extent.”

Chris Woodcock, the school’s deputy head teacher, said the school would not comment on individual cases, but reiterated its policy.

He said: “We continue to have consistent and clear expectations of all students in terms of uniform and personal presentation in school.

“Our expectations have been consistent for a number of years now and as a result of working closely with students and their parents – by confirming expectations and any specific changes in advance through letters, emails, on our website and through student planners and assemblies.

“The vast majority of students present themselves exceptionally well each and every day.”

In the last three weeks, Mr Farmer said he had spent around £20 on haircuts for Harry to try to rectify the problem, but to no avail.

“I know the school had a policy on extreme haircuts,” he said. “I went to the hairdressers with him and I wouldn’t have let him have it done if I thought it was too much.

“While I was there I saw about half a dozen kids with similar hair. It just seems ridiculous to me to put a child’s education at risk for something so petty.